1. Field of the Invention
This invention generally relates to hand tools and, more specifically, to an improved prying bar for moving or prying objects.
2. Description of the Prior Art
Numerous prying tools have been known, these exhibiting different configurations and sizes. All of the bars in this category operate on the principle of the simple first class lever. A first class lever is a lever wherein the load to be overcome is at or near one end of a rod or bar, and the effort or force is applied at or near the other end of the rod or bar, and the fulcrum, or pivot, is somewhere along the rod or bar inbetween the applied force and load. Thus, the user seeks to obtain a mechanical advantage by placing one end of the bar adjacent to the surface to be moved, and providing a pivot point about which a longer moment arm is provided so that substantial forces can be provided to the surface and/or the object to be pried open or moved. For example, one prying bar is a ripping bar in the form of a straight elongate bar having a generally hexagonal cross section and provided with a wedge or tapered end that can be forced between two adjacent surfaces. However, because such a ripping bar is a straight bar, it has limitations in the applications for which it can be used. For example, it is not convenient to use it when a heavy object has a surface in contact with a floor or has a surface which is in contact with a wall. Because the tapered or beveled edge must be inserted while the bar is substantially parallel to the floor or wall, respectively, it may be difficult in some instances for the bar to be held by the user since that portion of the bar which is held by the user's hand may be too close to or may abut an adjacent surface. A wrecking bar similarly has an elongate member of hex cross section provided with a tapered or beveled chisel tip, which may be somewhat offset from the longitudinal axis of the bar at one end. The other end of the bar is similarly provided with a tapered or beveled edge which is, however, bent between 90.degree. and 180.degree. so as to form a neck portion with the second beveled or tapered tip being directed in a direction substantially the same as the first tip. While this tool may be useful in applying prying forces to relatively small areas, such as automobile wrecks, it suffers the same aforementioned disadvantages of the ripping bar insofar as moving objects close to a floor or wall surface since such surfaces become obstacles to the convenient insertion of the tapered or beveled edges between the surfaces to be pried.
A prying bar is also known generally formed of flat steel material which has a tapered or beveled tip at one end and a neck portion which directs the beveled or tapered tip at the other end in a direction substantially normal to the longitudinaldirection of the bar extending between the tips. Aside from lacking the structural strength or integrity of the ripping and wrecking bars, which have a more substantial hexagonal cross section, directing the second beveled or tapered tip in a direction substantially normal to the longitudinal direction of the bar also makes it very difficult or inconvenient to place the second tip between surfaces that are close to a floor or to a wall since, again, the hand of a user typically abuts against the floor or the wall when the bar is held by the user during insertion of the tip between the surfaces. A nail puller is also known which has a substantially similar tip at the end of a bar with a hex cross section, in which the tip provided with the nail pulling slot is directed substantially normally to the longitudinal direction of the bar to which the user's hand applies a force.
There is also known a T-type wrecking bar which typically also has a hex cross section elongate bar provided with a tapered or beveled edge at one end, as with the wrecking bar. At the other end, however, there is provided a cross bar which is integrally formed at the end of the elongate bar to simulate a T-shape. Each end of the cross bar is itself tapered or beveled. In order to render this bar more useful, the end of the elongate bar which supports the cross bar is frequently bent somewhat between 5.degree. and 30.degree. so that one of the tapered or beveled edges on the cross bar forms a smaller angle with the elongate bar than does the other beveled or tapered edge of the cross bar. However, although one of the tips on the cross bar may be more convenient to insert between two surfaces than the other tip, this type of wrecking bar does not include a rounded neck portion about which pivoting action can take place. Instead, the pivoting action for each of the tips at the end of the cross bar is about the other tip of the same cross bar. Such arrangement is not always easy to use and becomes impractical in many applications.
Furthermore, because of the inherent limitations in the prior art bars, it was frequently necessary for a user to purchase and use more than one of the bar designs to accommodate different or specific applications.
Another disadvantage of some of the known prying bars, particularly the wrecking bar, is that the fulcrum for the pivoting action, between the prying arm and the moment arm, is the bent hex rod itself This results in a relatively small footprint area which creates extremely high concentrated stresses on the surface on which the pivoting action takes place. This frequently results in the "sinking" of the fulcrum into the surface and deformation and damage thereto.